/Engine/Source/Runtime/Core/Public/Misc/PathViews.h
Split the given absolute or relative path into its topmost directory and the relative path from that directory. Directory elements of . and .. are currently not interpreted and are treated as literal characters. Callers should not rely on this behavior as it may be corrected in the future. callers should instead conform the paths before calling.
static void SplitFirstComponent ( FStringView InPath, FStringView & OutFirstComponent, FStringView & OutRemainder )